This is the correct station after Abbey Junction.
There are conflicting sources about the location of Sleightholme station – especially on Wikipedia, where the station appears on the C&SBR route diagram but is omitted from the Solway Junction route diagram. There was only ever one station with the nam of Sleightholme; it served the settlement of Newton Arlosh a little to the north. The matter is resolved upon consulting
this six-inch map preserved on the National Library of Scotland website; the site of Sleightholme station is proven to lie between Abbey Junction and the junction of the C&SBR and the Solway Junction Rlwy just to the southwest of Kirkbride. In addition, Google Maps corroborates the co-ordinates of Sleightholme station as given by its Wikipedia page; not only does the cited location lie just to the northwest of a farmstead that lay in an area named on the NLS's six-inch map as 'Sleightholme' (here are matching screenshots),
but also a screenshot of the Streetview mode taken from the bridge over the old railway alignment depicts something that I believe to be the site of the old station at Sleightholme (demonstrated below).
Do we not travel ("running powers" situation) along a stretch of the Carlisle & Silloth Bay; between Abbey Jun., and the Solway Junction Ry. / C & SB divergence a little before Kirkbride -- which stretch includes Sleightholme?
I believe you are correct.
All evidence points to Sleightholme being located between Abbey Junction and Kirkbride Junction rather than being north of the latter; therefore, for future reference, I believe that the correct order of stations would be Abbey Junction > Sleightholme > Whitrigg. I hope this helps.